Operator precedence is essentially like an order of operations for Python's operators.
Example 1 (arithmetic)
2 * 3 + 1 is 7 because multiplication is first
2 * (3 + 1) is 8 because the parenthesis change the precedence allowing the sum to be first
Example 2 (logic)
not True or True is True because the not is first
not (True or True) is False because the or is first
The full table of precedence from lowest to highest is here